Alkali-free glass plate

ABSTRACT

The present invention provides an alkali-free glass sheet, which has a content of Li 2 O+Na 2 O+K 2 O of from 0 mol % to 0.5 mol % in a glass composition, and has a Young&#39;s modulus of 78 GPa or more, a strain point of 680° C. or more, and a liquidus temperature of 1,450° C. or less.

TECHNICAL FIELD

The present invention relates to an alkali-free glass sheet, and more specifically, to an alkali-free glass sheet suitable for an OLED display.

BACKGROUND ART

An electronic device, such as an OLED display, is used in applications such as a flexible device and a display of a cellular phone because the electronic device is thin, is excellent in displaying a moving image, and has low power consumption.

A glass sheet is widely used as a substrate of an OLED display. The glass sheet of this application is mainly required to satisfy the following characteristics.

(1) To be substantially free of an alkali metal oxide, that is, to be alkali-free glass (to have a content of an alkali metal oxide of 0.5 mol % or less in a glass composition) in order to prevent a situation in which an alkali ion is diffused in a heat treatment step into a semiconductor substance having been formed into a film. (2) To be excellent in productivity, particularly excellent in meltability and devitrification resistance in order to achieve a reduction in cost of the glass sheet. (3) To have a high strain point in order to reduce the thermal shrinkage of the glass sheet in a low temperature polysilicon (LIPS) process.

CITATION LIST

-   Patent Literature 1: JP 2012-106919 A

SUMMARY OF INVENTION Technical Problem

Incidentally, an OLED device has been widely deployed also in an OLED TV. The panel size of the OLED TV is much larger than that of a mobile product. It is expected that demands for an increase in size and a reduction in thickness of the glass sheet will increase in the future. As the size of the glass sheet is increased more and the thickness of the glass sheet is reduced more, the glass sheet is more liable to be deflected, and various defects are more liable to occur.

While the glass sheet formed by a glass manufacturer is subjected to steps such as cutting, annealing, inspection, and washing, the glass sheet is loaded into a cassette in which a plurality of shelves are formed during the steps and is conveyed. The cassette is generally configured so that opposing both sides of the glass sheet are placed on shelves formed on internal left and right surfaces thereof to allow the glass sheet to be held in a horizontal direction. However, a large and thin glass sheet has a large deflection amount, and hence part of the glass sheet is brought into contact with the cassette and the glass sheet is liable to be broken at the lime of loading of the glass sheet into the cassette, or the glass sheet largely swings and is liable to be unstable at the time of conveyance. The cassette having such configuration is also used in an electronic device manufacturer, resulting in occurrence of similar defects.

Further, as the size of the OLED device is increased more and the thickness of the OLED device is reduced more, the glass sheet is more liable to be deflected, resulting in a risk in that an image screen of the OLED TV may be seen in a distorted manner.

In order to solve the above-mentioned problems, a method involving increasing the Young's modulus of the glass sheet, to thereby reduce the deflection amount thereof is effective.

In addition, as described above, it is required that the strain point of the glass sheet be increased in order to reduce the thermal shrinkage of the glass sheet in the LTPS process.

However, when the Young's modulus and the strain point of the glass sheet are to be increased, the glass composition loses its balance, and the meltability and the devitrification resistance are reduced, with the result that the productivity of the glass sheet is liable to be reduced. As a result, the raw sheet cost of the glass sheet rises.

Thus, the present invention has been devised in view of the above-mentioned circumstances, and a technical object of the present invention is to provide an alkali-free glass sheet which is excellent in productivity and has a sufficiently high strain point and a sufficiently high Young's modulus.

Solution to Problem

The inventor of the present invention has repeated various experiments, and as a result, has found that the above-mentioned technical object can be achieved by strictly restricting the glass characteristics of an alkali-free glass sheet. Thus, the finding is proposed as the present invention. That is, according to one embodiment of the present invention, there is provided an alkali-free glass sheet, which has a content of Li₂O+Na₂O+K₂O of from 0 mol % to 0.5 mol % in a glass composition, and has a Young's modulus of 78 GPa or more, a strain point of 680° C. or more, and a liquidus temperature of 1,450° C. or less. Herein, the “Li₂O+Na₂O+K₂O” refers to the total content of Li₂O, Na₂O, and K₂O. The “Young's modulus” refers to a value measured by a flexural resonance method. 1 GPa corresponds to about 101.9 Kgf/mm². The “strain point” refers to a value measured based on a method of ASTM C336. The “liquidus temperature” refers to a temperature at which a crystal precipitates after glass powder having passed through a standard 30-mesh sieve (500 μm) and remained on a 50-mesh sieve (300 μm) is placed in a platinum boat and kept for 24 hours in a gradient heating furnace.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention comprise as the glass composition, in terms of mol %, 58% to 68% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 4% to 10% of MgO, 2% to 10% of CaO, and 2% to 13% of SrO+BaO. Herein, the “SrO+BaO” refers to the total content of SrO and BaO.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention comprise as the glass composition, in terms of mol %, 58% to 67% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 4% to 10% of MgO, 2% to 10% of CaO, 1.5% to 8% of SrO, and 1.5% to 8% of BaO, and be substantially free of As₂O₃ and Sb₂O₃. Herein, the “substantially free of As₂O₃ and Sb₂O₃” refers to the case in which the contents of As₂O₃ and Sb₂O₃ in the glass composition are each less than 0.05%.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention further comprise 0.001 mol % to 1 mol % of SnO₂.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention have a strain point of 690° C. or more.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention have a Young's modulus of more than 80 GPa.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention have an average thermal expansion coefficient within a temperature range of from 30° C. to 380° C. of from 30×10⁻⁷/° C. to 50×10⁻⁷/° C. Herein, the “average thermal expansion coefficient within a temperature range of from 30° C. to 380° C.” may be measured with a dilatometer.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention have a liquidus viscosity of 10^(4.5) dPa·s or more. Herein, the “liquidus viscosity” refers to a glass viscosity at the liquidus temperature, and may be measured by a platinum sphere pull up method.

In addition, it is preferred that the alkali-free glass sheet according to the one embodiment of the present invention be used for an OLED device.

DESCRIPTION OF EMBODIMENTS

An alkali-free glass sheet of the present invention preferably comprises as a glass composition, in terms of mol %, 58% to 72% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 0% to 10% of MgO, 0% to 10% of CaO, 0% to 8% of SrO, and 0% to 8% of BaO, more preferably comprises as a glass composition, in terms of mol %, 58% to 68% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 4% to 10% of MgO, 2% to 10% of CaO, and 2% to 13% of SrO+BaO. In particular, it is still more preferred that the alkali-free glass sheet of the present invention comprise as a glass composition, in terms of mol %, 58% to 67% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 4% to 10% of MgO, 2% to 10% of CaO, 1.5% to 8% of SrO, and 1.5% to 8% of BaO and be substantially free of As₂O₃ and Sb₂O₃. The reasons why the contents of the components are limited as describe above are described below. In the descriptions of the contents of the components, the expression “%” represents “mold”, unless otherwise specified.

SiO₂ is a component which forms the skeleton of glass. When the content of SiO₂ is too small, a thermal expansion coefficient is increased, and a density is increased. Accordingly, the lower limit content of SiO₂ is preferably 58%, still more preferably 59%, still more preferably 60%, still more preferably 61%, still more preferably 62%, still more preferably 63%, most preferably 64%. Meanwhile, when the content of SiO₂ is too large, a Young's modulus is reduced. Further, a viscosity at high temperature is increased, resulting in an increase in amount of heat required for melting. This causes a rise in melting cost, and in addition, leads to occurrence of defects due to an unmelted residue of a SiO₂ raw material, which may cause a reduction in yield. In addition, a devitrified crystal, such as cristobalite, is liable to precipitate, and a liquidus viscosity is liable to be reduced. Accordingly, the upper limit content of SiO₂ is preferably 72%, still more preferably 71%, still more preferably 70%, still more preferably 69.5%, still more preferably 69%, still more preferably 68%, most preferably 67%.

Al₂O₃ is a component which forms the skeleton of the glass, and is also a component which increases the Young's modulus, and is further a component which increases a strain point. When the content of Al₂O₃ is too small, the Young's modulus is liable to be reduced, and the strain point is liable to be reduced. Accordingly, the lower limit content of Al₂O₃ is preferably 11%, more preferably 11.2%, more preferably 11.4%, still more preferably 11.6%, still more preferably 11.8%, most preferably 12% Meanwhile, when the content of Al₂O₃ is too large, a devitrified crystal, such as mullite, is liable to precipitate, and the liquidus viscosity is liable to be reduced. Accordingly, the upper limit content of Al₂O₃ is preferably 18%, more preferably 17%, more preferably 16%, still more preferably 15.5%, still more preferably 15%, most preferably 14%.

The mole percent ratio SiO₂/Al₂O₃ is preferably from 4.2 to 5.8, more preferably from 4.5 to 5.5, particularly preferably from 4.8 to 5.3. When the ratio SiO₂/Al₂O₃ is too low, the strain point and/or devitrification resistance is liable to be reduced. Meanwhile, when the ratio SiO₂/Al₂O₃ is too high, the Young's modulus and/or meltability is liable to be reduced. The “SiO₂/Al₂O₃” refers to a value obtained by dividing the content of SiO₂ by the content of Al₂O₃.

B₂O₃ is a component which improves the meltability and the devitrification resistance. When the content of B₂O₃ is too small, the meltability and the devitrification resistance are liable to be reduced. Accordingly, the lower limit content of B₂O₃ is preferably 1.5%, more preferably 1.8%, more preferably 2.0%, still more preferably 2.2%, still more preferably 2.4%, most preferably 2.5%. Meanwhile, when the content of B₂O₃ is too large, the Young's modulus and the strain point are liable to be reduced. Accordingly, the upper limit content of B₂O₃ is preferably 6%, more preferably 5.7%, more preferably 5.3%, still more preferably 5.0%, still more preferably 4.8%, most preferably 4.5%.

The mole percent ratio Al₂O₃/B₂O₃ is preferably from 3 to 7.5, more preferably from 3.5 to 6, particularly preferably from 4 to 5. When the ratio Al₂O₃/B₂O₃ is too low, the Young's modulus is liable to be reduced. Meanwhile, when the ratio Al₂O₃/B₂O₃ is too high, the devitrification resistance is liable to be reduced. The “Al₂O₃/B₂O₃” refers to a value obtained by dividing the content of Al₂O₃ by the content of B₂O₃.

The total content of Li₂O, Na₂O, and K₂O is from 0% to 0.5%, preferably from 0% to 0.2%, more preferably from 0% to 0.15%. When the total content of Li₂O, Na₂O, and K₂O is too large, a situation in which an alkali ion is diffused in a heat treatment step into a semiconductor substance having been formed into a film may occur.

MgO is a component which remarkably increases the Young's modulus among alkaline earth metal oxides. When the content of MgO is too small, the meltability and the Young's modulus are liable to be reduced. Accordingly, the lower limit content of MgO is preferably 0%, more preferably 2%, more preferably 2.5%, still more preferably 3%, still more preferably 3.5%, still more preferably 4%, still more preferably 4.2%, most preferably 4.5%. Meanwhile, when the content of MgO is too large, a devitrified crystal, such as mullite, is liable to precipitate, and the liquidus viscosity is liable to be reduced. Accordingly, the upper limit content of MgO is preferably 10%, more preferably 9.5%, more preferably 9%, still more preferably 8.5%, still more preferably 8%, still more preferably 7.5%, still more preferably 7%, still more preferably 6.8%, most preferably 6.5%.

The mole percent ratio (Al₂O₃+MgO)/B₂O₃ is preferably from 3.5 to 10, more preferably from 4 to 8, particularly preferably from 4.5 to 6. When the ratio (Al₂O₃+MgO)/B₂O₃ is too low, the Young's modulus is liable to be reduced. Meanwhile, when the ratio (Al₂O₃+MgO)/B₂O₃ is too high, the devitrification resistance is liable to be reduced. The “(Al₂O₃+MgO)/B₂O₃” refers to a value obtained by dividing the total content of Al₂O₃ and MgO by the content of B₂O₃.

CaO is a component which reduces the viscosity at high temperature to remarkably improve the meltability without reducing the strain point. CaO is also a component which increases the Young's modulus. When the content of CaO is too small, the meltability is liable to be reduced. Accordingly, the lower limit content of CaO is preferably 0%, more preferably 2%, more preferably 2.5%, still more preferably 2.8%, still more preferably 3%, still more preferably 3.5%, still more preferably 3.8%, most preferably 4%. Meanwhile, when the content of CaO is too large, the thermal expansion coefficient may be improperly increased. Accordingly, the upper limit content of CaO is preferably 10%, more preferably 9.8%, more preferably 9.5%, still more preferably 9%, still more preferably 8.8%, still more preferably 8.5%, still more preferably 8%, still more preferably 7.8%, most preferably 7.5%.

SrO is a component which improves the devitrification resistance, and is further a component which reduces the viscosity at high temperature to improve the meltability without reducing the strain point. SrO is also a component which suppresses a reduction in liquidus viscosity. When the content of SrO is too small, it becomes difficult to exhibit the above-mentioned effects. Accordingly, the lower limit content of SrO is preferably 0%, more preferably 0.1%, more preferably 0.2%, still more preferably 0.3%, still more preferably 0.4%, still more preferably 0.5%, still more preferably 0.7%, still more preferably 0.8%, most preferably more than 1%. Meanwhile, when the content of SrO is too large, the thermal expansion coefficient and the density are liable to be increased. Accordingly, the upper limit content of SrO is preferably 8%, more preferably 7.5%, more preferably 7%, still more preferably 6.5%, most preferably 6%.

BaO is a component which improves the devitrification resistance. When the content of BaO is too small, it becomes difficult to exhibit the above-mentioned effect. Accordingly, the lower limit content of BaO is preferably 0%, more preferably 0.2%, more preferably 0.5%, still more preferably 1%, still more preferably 1.3%, most preferably 1.5%. Meanwhile, when the content of BaO is too large, the Young's modulus is liable to be reduced, and the thermal expansion coefficient and the density are liable to be increased. Accordingly, the upper limit content of BaO is preferably 10%, more preferably 8%, more preferably 7%, still more preferably 6%, still more preferably 5%, still more preferably 4%, most preferably 3.6%.

When the total content of MgO, CaO, SrO, and BaO is too small, the meltability is liable to be reduced. Accordingly, the lower limit of the total content of MgO, CaO, SrO, and BaO (RO) is preferably 13%, more preferably 14%, more preferably 15%, still more preferably 15.2%, most preferably 15.5%. Meanwhile, when the total content of MgO, CaO, SrO, and BaO is too large, the thermal expansion coefficient and the density are liable to be increased. Accordingly, the upper limit of the total content of MgO, CaO, SrO, and BaO (RO) is preferably 24%, more preferably 22%, more preferably 21%, still more preferably 20%, most preferably 19%.

When the total content of SrO and BaO is too small, the devitrification resistance and the meltability are liable to be reduced. Accordingly, the lower limit of the total content of SrO and BaO is preferably 0%, more preferably 1%, more preferably 1.5%, still more preferably 2%, most preferably 2.5%. Meanwhile, when the total content of SrO and BaO is too large, the Young's modulus is liable to be reduced, and the thermal expansion coefficient and the density are liable to be increased. Accordingly, the upper limit of the total content of SrO and BaO is preferably 13%, more preferably 10%, more preferably 8%, still more preferably 7%, still more preferably 6%, most preferably 5%.

The mole percent ratio (MgO+CaO)/(SrO+BaO) is preferably from 2.1 to 10, more preferably from 3 to 7, particularly preferably from 4 to 5. When the ratio (MgO+CaO)/(SrO+BaO) is too low, the Young's modulus is liable to be reduced. Meanwhile, when the ratio (MgO+CaO)/(SrO+BaO) is too high, the devitrification resistance is liable to be reduced. The “(MgO+CaO)/(SrO+BaO)” refers to a value obtained by dividing the total content of MgO and CaO by the total content of SrO and BaO.

For example, the following components may be added as optional components in addition to the above-mentioned components. The content of the components other than the above-mentioned components, in terms of total content, is preferably 10% or less, particularly preferably 5% or less from the viewpoint of appropriately exhibiting the effects of the present invention.

ZnO is a component which increases the meltability. However, when ZnO is contained in a large amount, the glass is liable to devitrify, and in addition, the strain point is liable to be reduced. The content of ZnO is preferably from 0% to 5%, from 0% to 3%, or from 0% to 2%, particularly preferably from 0% to less than 1%.

P₂O₅ is a component which increases the strain point, and is also a component which can remarkably suppress the precipitation of an alkaline earth aluminosilicate-based devitrified crystal, such as anorthite. However, when P₂O₅ is contained in a large amount, the glass is liable to undergo phase separation. The content of P₂O₅ is preferably from 0% to 2.5%, more preferably from 0.0005% to 1.5%, still more preferably from 0.001% to 0.5%, particularly preferably from 0.005% to 0.3%.

The mole percent ratio Al₂O₃/(10,000×P₂O₃) is preferably from 0.12 to 10, more preferably from 0.2 to 5, particularly preferably from 0.3 to 2. When the ratio Al₂O₃/(10,000×P₂O₃) is too low, the Young's modulus is liable to be reduced. Meanwhile, when the ratio Al₂O₃/(10,000×P₂O₅) is too high, the alkaline earth aluminosilicate-based devitrified crystal, such as anorthite, is liable to precipitate. The “Al₂O₃/(10,000×P₂O₅)” refers to a value obtained by dividing the content of Al₂O₃ by the content of P₂O₅ multiplied by 10,000.

TiO₂ is a component which reduces the viscosity at high temperature to improve the meltability, and is also a component which suppresses solarization. However, when TiO₂ is contained in a large amount, the glass is colored, and thus a transmittance is liable to be reduced. The content of TiO₂ is preferably from 0% to 2.5%, more preferably from 0.0005% to 1%, still more preferably from 0.001% to 0.5%, particularly preferably from 0.005% to 0.1%.

The mole percent ratio Al₂O₃/(1,000×TiO₂) is preferably from 0.1 to 10, more preferably from 0.6 to 4, particularly preferably from 1.1 to 1.6. When the ratio Al₂O₃/(1,000×TiO₂) is too low, the Young's modulus is liable to be reduced. Meanwhile, when the ratio Al₂O₃/(1,000×TiO₂) is too high, the meltability and solarization resistance are liable to be reduced. The “Al₂O₃/(1,000×TiO₂)” refers to a value obtained by dividing the content of Al₂O₃ by the content of TiO₂ multiplied by 1,000.

Y₂O₃, Nb₂O₅, and La₂O₃ each have an action of increasing the strain point, the Young's modulus, and the like. The total content and the individual contents of those components are each preferably from 0% to 5%, more preferably from 0% to 1%, still more preferably from 0% to 0.5%. When the total content and the individual contents of Y₂O₃, Nb₂O₅, and La₂O₃ are too large, the density and raw material cost are liable to be increased.

SnO₂ is a component which exhibits a satisfactory fining action in a high temperature region. In addition, SnO₂ is a component which increases the strain point, and is also a component which reduces the viscosity at high temperature. The content of SnO₂ is preferably from 0% to 1%, from 0.001% to 1%, or from 0.01% to 0.5%, particularly preferably from 0.05% to 0.3%. When the content of SnO₂ is too large, a devitrified crystal of SnO₂ is liable to precipitate. When the content of SnO₂ is less than 0.001%, it becomes difficult to exhibit the above-mentioned effects.

SnO₂ is suitable as a fining agent as describe above, but unless glass characteristics are impaired, F, SO₃, C, or metal powder, such as Al or Si, may each be added as a fining agent at up to 5% (preferably up to 1%, particularly preferably up to 0.5%). In addition, CeO₂ or the like may also be added as a fining agent at up to 5% (preferably up to 1%, particularly preferably up to 0.5%).

As₂O₃ and Sb₂O₃ are each effective as a fining agent. However, the alkali-free glass sheet of the present invention is substantially free of those components from an environmental viewpoint. Further, when As₂O₃ is contained, the solarization resistance tends to be reduced.

Cl is a component which promotes initial melting of a glass batch. In addition, when Cl is added, the action of the fining agent can be promoted. As a result thereof, while the melting cost is reduced, the lifetime of a glass production kiln can be prolonged. However, when the content of Cl is too large, the strain point is liable to be reduced. Accordingly, the content of Cl is preferably from 0% to 3%, more preferably from 0.0005% to 1%, particularly preferably from 0.001% to 0.5%. The following raw material may be used as a raw material for introducing Cl: an alkaline earth metal chloride, such as strontium chloride, aluminum chloride, or the like.

Fe₂O₃ is a component which is mixed in as a raw material impurity, and is also a component which reduces an electrical resistivity. The content of Fe₂O₃ is preferably from 0 ppm by mass to 300 ppm by mass or from 80 ppm by mass to 250 ppm by mass, particularly preferably from 100 ppm by mass to 200 ppm by mass. When the content of Fe₂O₃ is too small, the raw material cost is liable to rise. Meanwhile, when the content of Fe₂O₃ is too large, it becomes difficult to perform electric melting owing to an increase in electrical resistivity of the molten glass.

The alkali-free glass sheet of the present invention preferably has the following characteristics.

The average thermal expansion coefficient within a temperature range of from 30° C. to 380° C. is preferably from 30×10⁻⁷/° C. to 50×10⁻⁷/° C., from 32×10⁻⁷/° C. to 48×10⁻⁷/° C., from 33×10⁻⁷/° C. to 45×10⁻⁷/° C., or from 34×10⁻⁷/° C. to 44×10⁻⁷/° C., particularly preferably from 35×10⁻⁷/° C. to 44×10⁻⁷/° C. With this configuration, the thermal expansion coefficient easily matches the thermal expansion coefficient of Si to be used for a TFT.

The Young's modulus is 78 GPa or more, preferably more than 78 GPa or 80 GPa or more, particularly preferably 81 GPa or more. When the Young's modulus is too low, defects due to the deflection of the glass sheet are liable to occur.

The strain point is 680° C. or more, preferably more than 680° C. or 690° C. or more, particularly preferably 700° C. or more. With this configuration, the thermal shrinkage of the glass sheet can be suppressed in a LTPS process.

The liquidus temperature is 1,450° C. or less, preferably less than 1,210° C. or 1,200° C. or less, particularly preferably 1,190° C. or less. With this configuration, a situation in which a devitrified crystal is generated at the time of glass production, resulting in a reduction in productivity, is easily prevented. Further, the glass sheet is easily formed by an overflow down-draw method, and hence the surface quality of the glass sheet is easily improved. Besides, the manufacturing cost of the glass sheet can be reduced. The liquidus temperature serves as an indicator of the devitrification resistance. As the liquidus temperature becomes lower, the devitrification resistance is more excellent.

The liquidus viscosity is preferably 10^(4.8) dPa·s or more, 10^(5.0) dPa·s or more, or 10^(5.2) dPa·s or more, particularly preferably 10^(5.3) dPa·s or more. With this configuration, devitrification is less liable to occur at the time of forming, and hence the glass sheet is easily formed by an overflow down-draw method. As a result, the surface quality of the glass sheet can be improved. Besides, the manufacturing cost of the glass sheet can be reduced. The liquidus viscosity serves as indicators of the devitrification resistance and the formability. As the liquidus viscosity becomes higher, the devitrification resistance and the formability are improved more.

The temperature at a viscosity at high temperature of 10^(2.5) dPa·s is preferably 1,650° C. or less, 1,600° C. or less, or 1,580° C. or less, particularly preferably 1,560° C. or less. When the temperature at a viscosity at high temperature of 10^(2.5) dPa·s is too high, it becomes difficult to melt a glass batch, resulting in a rise in manufacturing cost of the glass sheet. The temperature at a viscosity at high temperature of 10^(2.5) dPa·s corresponds to a melting temperature. As the temperature becomes lower, the meltability is improved more.

The β-OH is an indicator of the amount of water in the glass. When the 3-OH is reduced, the strain point can be increased. In addition, even with the same glass composition, a glass sheet having lower β-OH has a lower thermal shrinkage rate at a temperature equal to or lower than the strain point. The β-OH is preferably 0.30/mm or less, 0.25/mm or less, 0.20/mm or less, or 0.15/mm or less, particularly preferably 0.10/mm or less. When the β-OH is too low, the meltability is liable to be reduced. Accordingly, the β-OH is preferably 0.01/mm or more, particularly preferably 0.03/mm or more.

As a method of reducing the β-OH, the following methods are given: (1) a method involving selecting raw materials having low water contents; (2) a method involving adding a component (such as Cl or SO₃) which reduces the β-OH to the glass; (3) a method involving reducing the amount of water in a furnace atmosphere; (4) a method involving performing N₂ bubbling in molten glass; (5) a method involving adopting a small melting furnace; (6) a method involving increasing the flow rate of molten glass; and (7) a method involving adopting an electric melting method.

Herein, the “β-OH” refers to a value determined using the following mathematical formula by measuring the transmittances of the glass with an FT-IR.

β-OH=(1/X)Log(T ₁ /T ₂)

X: Thickness (mm)

T₁: Transmittance (%) at a reference wavelength of 3,846 cm⁻¹

T₂: Minimum transmittance (%) at a wavelength around a hydroxyl group absorption wavelength of 3,600 cm⁻¹

It is preferred that the alkali-free glass sheet of the present invention be formed by an overflow down-draw method. The overflow down-draw method refers to a method in which molten glass is caused to overflow from both sides of a heat-resistant trough-shaped structure, and the overflowing molten glasses are subjected to down-draw downward at the lower end of the trough-shaped structure while being joined, to thereby produce the glass sheet. By the overflow down-draw method, surfaces which are to serve as the surfaces of the glass sheet are formed in a state of free surfaces without being brought into contact with the trough-shaped refractory. As a result, a glass sheet having good surface quality can be manufactured without polishing at low cost, and a reduction in thickness is easily achieved as well.

Other than the overflow down-draw method, the glass sheet may be formed by, for example, a down-draw method (such as a slot down method) or a float method.

The sheet thickness of the alkali-free glass sheet of the present invention is not particularly limited, but is preferably less than 0.7 mm, 0.6 mm or less, or 0.5 mm or less, particularly preferably 0.4 mm or less. As the thickness becomes smaller, the weight saving of an OLED device can be achieved more. The sheet thickness may be adjusted based on, for example, a flow rate and a sheet-drawing speed at the time of glass production.

The alkali-free glass sheet of the present invention is preferably used for an OLED device, particularly for an OLED TV. In OLED TV applications, a plurality of devices are formed on the glass sheet, and the glass sheet is then cut and divided into the respective devices to achieve cost-cutting (so-called multiple patterning). The alkali-free glass sheet of the present invention has a low liquidus temperature and a high liquidus viscosity, and hence a large glass sheet is easily formed, and thus such demand can be appropriately satisfied.

Examples

The present invention is hereinafter described by way of Examples. Examples below are merely examples, and the present invention is by no means limited to Examples below.

Examples (Sample Nos. 1 to 137) and Comparative Examples (Sample Nos. 138 to 141) of the present invention are shown in Tables 1 to 14.

TABLE 1 No. No. No. No. No. No. No. No. No. No. 1 2 3 4 5 6 7 8 9 10 Glass SiO₂ 64.9 61.9 64.9 62.4 63.4 62.9 60.4 60.9 59.5 61.7 compo- Al₂O₃ 12.0 12.0 12.0 12.5 12.5 12.0 12.5 12.0 12.5 12.5 sition B₂O₃ 5.0 5.0 2.0 5.0 5.0 5.0 5.0 4.0 4.0 5.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 6.0 7.0 7.0 8.0 8.0 7.0 6.0 8.0 8.5 8.0 CaO 6.0 7.0 7.0 5.0 4.0 5.0 6.0 8.0 7.6 3.0 SrO 3.0 3.5 3.5 3.5 3.5 5.0 4.0 3.0 4.0 6.8 BaO 3.0 3.5 3.5 3.5 3.5 3.0 6.0 4.0 3.8 3.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.002 0.002 0.003 0.002 0.011 0.005 0.002 0.003 0.011 0.002 TiO₂ 0.012 0.012 0.012 0.012 0.01 0.008 0.013 0.012 0.012 0.011 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.41 5.16 5.41 4.99 5.07 5.24 4.83 5.08 4.76 4.94 Al₂O₃/B₂O₃ 2.40 2.40 6.00 2.50 2.50 2.40 2.50 3.00 3.13 2.50 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 3.60 3.80 9.50 4.10 4.10 3.80 3.70 5.00 5.30 4.10 RO 18.0 21.0 21.0 20.0 19.0 20.0 22.0 23.0 23.9 20.8 SrO + BaO 6.0 7.0 7.0 7.0 7.0 8.0 10.0 7.0 7.8 9.8 (MgO + CaO)/(SrO + BaO) 2.00 2.00 2.00 1.86 1.71 1.50 1.20 2.29 2.06 1.12 Al₂O₃/(10,000 × P₂O₅) 0.60 0.60 0.40 0.63 0.11 0.24 0.63 0.40 0.11 0.63 Al₂O₃/(1,000 × TiO₂) 1.00 1.00 1.00 1.04 1.25 1.50 0.96 1.00 1.04 1.14 CTE [×10⁻⁷/° C.] 41.9 45.6 45.2 43.6 42.1 44.7 49.5 48.3 49.4 45.5 Density [g/cm³] 2.62 2.69 2.70 2.67 2.66 2.68 2.78 2.72 2.74 2.72 Young's modulus [GPa] 80 81 83 82 81 81 80 83 84 82 Ps [° C.] 690 681 708 690 693 690 682 688 688 689 Ta [° C.] 745 733 762 743 747 743 735 738 737 742 Ts [° C.] 966 940 976 953 962 955 939 939 931 949 10⁴ dPa · s [° C.] 1,267 1,220 1,267 1,233 1,250 1,238 1,214 1,204 1,186 1,225 10³ dPa · s [° C.] 1,421 1,366 1,416 1,378 1,398 1,385 1,356 1,346 1,321 1,365 10^(2.5) dPa · s [° C.] 1,522 1,461 1,513 1,471 1,493 1,481 1,446 1,434 1,406 1,459 TL [° C.] 1,130 1,154 1,217 1,202 1,220 1,205 1,154 1,165 1,161 1,212 Log₁₀ηTL 5.3 4.6 5.3 4.6 4.6 4.6 5.6 4.8 4.6 4.5

TABLE 2 No. No. No. No. No. No. No. No. No. No. 11 12 13 14 15 16 17 18 19 20 Glass SiO₂ 60.4 58.3 58.0 60.4 62.9 62.4 62.4 64.4 62.4 62.4 compo- Al₂O₃ 12.5 14.0 15.2 14.5 12.5 12.5 12.5 12.5 12.5 12.5 sition B₂O₃ 5.0 4.0 4.5 5.0 5.0 5.0 5.0 5.0 5.0 5.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 8.0 8.0 7.0 8.0 5.0 8.0 8.0 8.0 8.0 8.0 CaO 5.0 8.0 7.0 3.0 9.0 5.0 3.0 3.0 5.0 3.0 SrO 5.0 2.5 4.0 3.5 1.5 3.5 4.5 1.8 1.8 2.3 BaO 4.0 5.1 4.2 5.5 4.0 3.5 4.5 5.3 5.3 6.8 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.003 0.011 0.011 0.002 0.005 0.003 0.002 0.005 0.003 0.002 TiO₂ 0.012 0.011 0.01 0.008 0.013 0.012 0.011 0.012 0.012 0.011 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 4.83 4.16 3.82 4.17 5.03 4.99 4.99 5.15 4.99 4.99 Al₂O₃/B₂O₃ 2.50 3.50 3.38 2.90 2.50 2.50 2.50 2.50 2.50 2.50 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 4.10 5.50 4.90 4.50 3.50 4.10 4.10 4.10 4.10 4.10 RO 22.0 23.6 22.2 20.0 19.5 20.0 20.0 18.0 20.0 20.0 SrO + BaO 9.0 7.6 8.2 9.0 5.5 7.0 9.0 7.1 7.1 9.1 (MgO + CaO)/(SrO + BaO) 1.44 2.11 1.71 1.22 2.55 1.86 1.22 1.55 1.83 1.21 Al₂O₃/(10,000 × P₂O₅) 0.42 0.13 0.14 0.73 0.25 0.42 0.63 0.25 0.42 0.63 Al₂O₃/(1,000 × TiO₂) 1.04 1.27 1.52 1.81 0.96 1.04 1.14 1.04 1.04 1.14 CTE [×10⁻⁷/° C.] 47.4 49.2 47.7 44.1 44.9 43.6 44.3 40.7 43.9 44.6 Density [g/cm³] 2.73 2.77 2.76 2.75 2.65 2.67 2.71 2.67 2.69 2.74 Young's modulus [GPa] 82 85 84 82 80 82 81 80 81 80 Ps [° C.] 684 693 700 696 692 690 689 694 688 686 Ta [° C.] 735 743 751 749 746 743 743 749 741 740 Ts [° C.] 937 934 942 956 958 953 955 971 953 955 10⁴ dPa · s [° C.] 1,205 1,183 1,188 1,228 1,241 1,233 1,240 1,272 1,238 1,247 10³ dPa · s [° C.] 1,344 1,314 1,315 1,365 1,391 1,378 1,386 1,427 1,386 1,396 10^(2.5) dPa · s [° C.] 1,433 1,394 1,396 1,452 1,483 1,471 1,480 1,523 1,478 1,489 TL [° C.] 1,176 1,157 1,182 1,207 1,179 1,202 1,207 1,223 1,187 1,188 Log₁₀ηTL 4.8 4.9 4.6 5.0 4.9 4.6 4.9 5.0 5.1 5.5

TABLE 3 No. No. No. No. No. No. No. No. No. No. 21 22 23 24 25 26 27 28 29 30 Glass SiO₂ 64.9 64.9 64.9 64.9 64.9 64.9 65.9 65.9 65.9 65.9 compo- Al₂O₃ 14.0 14.0 14.0 14.0 14.0 14.0 13.0 13.0 13.0 13.0 sition B₂O₃ 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 6.0 5.0 5.0 4.0 4.0 4.0 7.0 6.0 6.0 5.0 CaO 7.0 8.0 7.0 9.0 8.0 7.0 7.0 8.0 7.0 9.0 SrO 2.0 2.0 2.5 2.0 2.5 3.0 1.5 1.5 2.0 1.5 BaO 2.0 2.0 2.5 2.0 2.5 3.0 1.5 1.5 2.0 1.5 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.003 0.003 0.003 0.004 0.004 0.004 0.005 0.005 0.003 0.003 TiO₂ 0.012 0.012 0.011 0.011 0.012 0.011 0.012 0.012 0.012 0.012 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 4.64 4.64 4.64 4.64 4.64 4.64 5.07 5.07 5.07 5.07 Al₂O₃/B₂O₃ 3.50 3.50 3.50 3.50 3.50 3.50 3.25 3.25 3.25 3.25 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 5.00 4.75 4.75 4.50 4.50 4.50 5.00 4.75 4.75 4.50 RO 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 SrO + BaO 4.0 4.0 5.0 4.0 5.0 6.0 3.0 3.0 4.0 3.0 (MgO + CaO)/(SrO + BaO) 3.25 3.25 2.40 3.25 2.40 1.83 4.67 4.67 3.25 4.67 Al₂O₃/(10,000 × P₂O₅) 0.47 0.47 0.47 0.35 0.35 0.35 0.26 0.26 0.43 0.43 Al₂O₃/(1,000 × TiO₂) 1.17 1.17 1.27 1.27 1.17 1.27 1.08 1.08 1.08 1.08 CTE [×10⁻⁷/° C.] 38.9 39.7 39.8 40.3 40.5 41.2 40.4 38.9 39.1 39.4 Density [g/cm³] 2.59 2.59 2.61 2.59 2.61 2.63 2.55 2.56 2.58 2.56 Young's modulus [GPa] 83 82 82 82 81 81 83 83 82 82 Ps [° C.] 717 716 715 716 715 715 712 713 712 712 Ta [° C.] 772 771 770 771 771 771 767 768 767 767 Ts [° C.] 993 992 992 992 993 944 989 991 989 989 10⁴ dPa · s [° C.] 1,282 1,283 1,288 1,284 1,293 1,287 1,282 1,282 1,285 1,284 10³ dPa · s [° C.] 1,430 1,433 1,439 1,434 1,444 1,437 1,433 1,432 1,438 1,437 10^(2.5) dPa · s [° C.] 1,526 1,529 1,536 1,531 1,544 1,534 1,531 1,530 1,539 1,536 TL [° C.] 1,177 1,216 1,205 1,230 1,210 1,215 1,184 1,185 1,181 1,208 Log₁₀ηTL 5.0 4.6 4.8 4.5 4.7 4.5 4.9 4.9 5.0 4.7

TABLE 4 No. No. No. No. No. No. No. No. No. No. 31 32 33 34 35 36 37 38 39 40 Glass SiO₂ 65.6 65.6 66.9 66.9 66.9 66.9 66.9 66.9 65.9 65.9 compo- Al₂O₃ 13.0 13.1 12.0 12.0 12.0 12.0 12.0 12.0 14.0 14.0 sition B₂O₃ 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 3.0 3.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 5.1 5.1 8.0 7.0 7.0 6.0 6.0 6.0 6.0 5.0 CaO 7.4 7.8 7.0 8.0 7.0 9.0 8.0 7.0 7.0 8.0 SrO 2.4 2.2 1.0 1.0 1.5 1.0 1.5 2.0 2.0 2.0 BaO 2.4 2.2 1.0 1.0 1.5 1.0 1.5 2.0 2.0 2.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.004 0.003 0.005 0.005 0.004 0.005 0.004 0.003 0.003 0.003 TiO₂ 0.012 0.012 0.012 0.012 0.011 0.012 0.012 0.012 0.011 0.011 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.03 5.02 5.58 5.58 5.58 5.58 5.58 5.58 4.71 4.71 Al₂O₃/B₂O₃ 3.26 3.28 3.00 3.00 3.00 3.00 3.00 3.00 4.67 4.67 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 4.54 4.56 5.00 4.75 4.75 4.50 4.50 4.50 6.67 6.33 RO 17.2 17.2 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 SrO + BaO 4.8 4.3 2.0 2.0 3.0 2.0 3.0 4.0 4.0 4.0 (MgO + CaO)/(SrO + BaO) 2.62 2.99 7.50 7.50 4.67 7.50 4.67 3.25 3.25 3.25 Al₂O₃/(10,000 × P₂O₅) 0.33 0.44 0.24 0.24 0.30 0.24 0.30 0.40 0.47 0.47 Al₂O₃/(1,000 × TiO₂) 1.09 1.09 1.00 1.00 1.09 1.00 1.00 1.00 1.27 1.27 CTE [×10⁻⁷/° C.] 40.0 39.9 36.7 37.6 38.0 38.4 38.7 39.3 38.7 39.6 Density [g/cm³] 2.59 2.59 2.52 2.52 2.54 2.53 2.54 2.57 2.59 2.59 Young's modulus [GPa] 81 81 83 82 82 82 81 81 83 83 Ps [° C.] 709 708 708 708 708 707 706 706 726 727 Ta [° C.] 765 764 763 763 763 762 762 762 781 782 Ts [° C.] 989 989 986 987 989 986 987 988 1,003 1,003 10⁴ dPa · s [° C.] 1,292 1,289 1,291 1,291 1,287 1,286 1,291 1,292 1,297 1,297 10³ dPa · s [° C.] 1,447 1,443 1,445 1,452 1,442 1,442 1,446 1,450 1,447 1,448 10^(2.5) dPa · s [° C.] 1,548 1,543 1,546 1,556 1,542 1,544 1,550 1,552 1,544 1,545 TL [° C.] 1,209 1,190 1,217 1,232 1,222 1,211 1,185 1,162 1,227 1,247 Log₁₀ηTL 4.7 4.9 4.6 4.5 4.6 4.7 5.0 5.2 4.6 4.4

TABLE 5 No. No. No. No. No. No. No. No. No. No. 41 42 43 44 45 46 47 48 49 50 Glass SiO₂ 65.9 65.9 65.9 65.9 66.9 66.9 66.9 66.9 66.9 66.9 compo- Al₂O₃ 14.0 14.0 14.0 14.0 13.0 13.0 13.0 13.0 13.0 13.0 sition B₂O₃ 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 5.0 4.0 4.0 4.0 7.0 6.0 6.0 5.0 5.0 5.0 CaO 7.0 9.0 8.0 7.0 7.0 8.0 7.0 9.0 8.0 7.0 SrO 2.5 2.0 2.5 3.0 1.5 1.5 2.0 1.5 2.0 2.5 BaO 2.5 2.0 2.5 3.0 1.5 1.5 2.0 1.5 2.0 2.5 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.003 0.003 0.003 0.002 0.003 0.003 0.003 0.003 0.003 0.003 TiO₂ 0.013 0.012 0.011 0.012 0.012 0.012 0.011 0.012 0.012 0.012 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 4.71 4.71 4.71 4.71 5.15 5.15 5.15 5.15 5.15 5.15 Al₂O₃/B₂O₃ 4.67 4.67 4.67 4.67 4.33 4.33 4.33 4.33 4.33 4.33 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 6.33 6.00 6.00 6.00 6.67 6.33 6.33 6.00 6.00 6.00 RO 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 SrO + BaO 5.0 4.0 5.0 6.0 3.0 3.0 4.0 3.0 4.0 5.0 (MgO + CaO)/(SrO + BaO) 2.40 3.25 2.40 1.83 4.67 4.67 3.25 4.67 3.25 2.40 Al₂O₃/(10,000 × P₂O₅) 0.47 0.47 0.47 0.70 0.43 0.43 0.43 0.43 0.43 0.43 Al₂O₃/(1,000 × TiO₂) 1.08 1.17 1.27 1.17 1.08 1.08 1.18 1.08 1.08 1.08 CTE [×10⁻⁷/° C.] 40.0 40.2 40.6 41.1 38.0 38.4 39.0 39.3 39.6 39.4 Density [g/cm³] 2.61 2.59 2.62 2.64 2.56 2.56 2.58 2.56 2.58 2.60 Young's modulus [GPa] 83 83 82 82 84 84 83 83 82 82 Ps [° C.] 726 727 725 725 723 722 721 721 720 720 Ta [° C.] 782 783 782 782 779 777 777 777 776 776 Ts [° C.] 1,004 1,004 1,005 1,006 1,001 1,000 1,002 1,000 1,001 1,003 10⁴ dPa · s [° C.] 1,302 1,300 1,303 1,307 1,300 1,301 1,305 1,303 1,306 1,309 10³ dPa · s [° C.] 1,453 1,450 1,456 1,459 1,453 1,455 1,460 1,457 1,462 1,466 10^(2.5) dPa · s [° C.] 1,550 1,548 1,554 1,558 1,552 1,554 1,563 1,557 1,562 1,567 TL [° C.] 1,216 1,251 1,253 1,249 1,199 1,208 1,210 1,239 1,216 1,211 Log₁₀ηTL 4.8 4.4 4.4 4.5 4.9 4.8 4.9 4.6 4.8 4.9

TABLE 6 No. No. No. No. No. No. No. No. No. No. 51 52 53 54 5 5 56 57 58 59 60 Glass SiO₂ 67.9 67.9 67.9 67.9 67.9 65.9 65.9 64.9 64.9 65.9 compo- Al₂O₃ 12.0 12.0 12.0 12.0 12.0 13.0 13.0 14.0 14.0 13.0 sition B₂O₃ 3.0 3.0 3.0 3.0 3.0 4.0 4.0 4.0 4.0 4.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 8.0 7.0 7.0 6.0 6.0 5.0 5.0 7.0 6.0 7.0 CaO 7.0 8.0 7.0 8.0 7.0 8.0 7.0 6.0 6.0 6.0 SrO 1.0 1.0 1.5 1.5 2.0 2.0 2.5 2.0 2.5 2.0 BaO 1.0 1.0 1.5 1.5 2.0 2.0 2.5 2.0 2.5 2.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.004 0.004 0.005 0.004 0.004 0.003 0.003 0.003 0.003 0.003 TiO₂ 0.013 0.012 0.012 0.012 0.012 0.011 0.012 0.012 0.012 0.012 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.66 5.66 5.66 5.66 5.66 5.07 5.07 4.64 4.64 5.07 Al₂O₃/B₂O₃ 4.00 4.00 4.00 4.00 4.00 3.25 3.25 3.50 3.50 3.25 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 6.67 6.33 6.33 6.00 6.00 4.50 4.50 5.25 5.00 5.00 RO 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 SrO + BaO 2.0 2.0 3.0 3.0 4.0 4.0 5.0 4.0 5.0 4.0 (MgO + CaO)/(SrO + BaO) 7.50 7.50 4.67 4.67 3.25 3.25 2.40 3.25 2.40 3.25 Al₂O₃/(10,000 × P₂O₅) 0.30 0.30 0.24 0.30 0.30 0.43 0.43 0.47 0.47 0.43 Al₂O₃/(1,000 × TiO₂) 0.92 1.00 1.00 1.00 1.00 1.18 1.08 1.17 1.17 1.08 CTE [×10⁻⁷/° C.] 36.0 37.5 37.9 38.6 39.1 39.7 40.0 38.3 39.3 38.5 Density [g/cm³] 2.52 2.53 2.55 2.55 2.57 2.58 2.60 2.58 2.60 2.57 Young's modulus [GPa] 84 84 83 83 83 82 82 83 82 82 Ps [° C.] 718 717 716 717 715 712 710 718 716 712 Ta [° C.] 774 773 772 773 771 768 766 772 772 767 Ts [° C.] 998 998 999 1,001 999 990 991 991 993 990 10⁴ dPa · s [° C.] 1,304 1,304 1,306 1,306 1,315 1,292 1,294 1,283 1,288 1,288 10³ dPa · s [° C.] 1,461 1,461 1,464 1,465 1,483 1,446 1,448 1,432 1,438 1,440 10^(2.5) dPa · s [° C.] 1,570 1,570 1,567 1,568 1,592 1,548 1,548 1,530 1,535 1,539 TL [° C.] 1,244 1,258 1,222 1,221 1,234 1,201 1,198 1,193 1,200 1,193 Log₁₀ηTL 4.5 4.4 4.7 4.7 4.7 4.8 4.9 4.8 4.8 4.9

TABLE 7 No. No. No. No. No. No. No. No. No. No. 61 62 63 64 65 66 67 68 69 70 Glass SiO₂ 65.9 64.9 64.9 65.9 65.9 66.9 66.9 65.9 65.9 65.9 compo- Al₂O₃ 13.0 14.0 14.0 13.0 13.0 12.0 12.0 14.0 14.0 14.0 sition B₂O₃ 4.0 4.0 4.0 4.0 4.0 4.0 4.0 3.0 3.0 3.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 6.0 6.0 6.0 6.0 6.0 7.0 6.0 7.0 6.0 5.0 CaO 6.0 7.0 7.0 7.0 7.0 6.0 6.0 6.0 6.0 6.0 SrO 2.5 4.0 0.0 4.0 0.0 2.0 2.5 2.0 2.5 3.0 BaO 2.5 0.0 4.0 0.0 4.0 2.0 2.5 2.0 2.5 3.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.003 0.003 0.003 0.003 0.003 0.004 0.003 0.003 0.002 0.002 TiO₂ 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.011 0.011 0.011 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.07 4.64 4.64 5.07 5.07 5.58 5.58 4.71 4.71 4.71 Al₂O₃/B₂O₃ 3.25 3.50 3.50 3.25 3.25 3.00 3.00 4.67 4.67 4.67 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 4.75 5.00 5.00 4.75 4.75 4.75 4.50 7.00 6.67 6.33 RO 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 SrO + BaO 5.0 4.0 4.0 4.0 4.0 4.0 5.0 4.0 5.0 6.0 (MgO + CaO)/(SrO + BaO) 2.40 3.25 3.25 3.25 3.25 3.25 2.40 3.25 2.40 1.83 Al₂O₃/(10,000 × P₂O₅) 0.43 0.47 0.47 0.43 0.43 0.30 0.40 0.47 0.70 0.70 Al₂O₃/(1,000 × TiO₂) 1.08 1.17 1.17 1.08 1.08 1.00 1.00 1.27 1.27 1.27 CTE [×10⁻⁷/° C.] 39.6 38.7 39.0 38.7 39.3 38.4 39.2 38.2 39.3 40.4 Density [g/cm³] 2.60 2.56 2.61 2.55 2.60 2.56 2.59 2.59 2.61 2.63 Young's modulus [GPa] 81 83 82 83 81 82 81 84 83 82 Ps [° C.] 710 718 715 713 710 707 707 727 726 725 Ta [° C.] 766 773 771 768 766 762 762 782 782 782 Ts [° C.] 991 990 992 988 990 988 989 1,002 1,010 1,006 10⁴ dPa · s [° C.] 1,294 1,281 1,285 1,282 1,291 1,291 1,296 1,298 1,303 1,308 10³ dPa · s [° C.] 1,450 1,430 1,434 1,432 1,443 1,450 1,455 1,449 1,454 1,461 10^(2.5) dPa · s [° C.] 1,551 1,528 1,531 1,531 1,542 1,552 1,556 1,547 1,552 1,559 TL [° C.] 1,178 1,220 1,186 1,213 1,162 1,170 1,180 1,200 1,205 1,191 Log₁₀ηTL 5.1 4.6 4.9 4.6 5.2 5.1 5.0 4.9 4.9 5.1

TABLE 8 No. No. No. No. No. No. No. No. No. No. 71 72 73 74 75 76 77 78 79 80 Glass SiO₂ 65.9 65.9 64.9 64.9 64.9 64.9 66.9 66.9 67.9 67.9 compo- Al₂O₃ 13.0 14.0 14.0 14.0 14.0 13.0 13.0 13.0 12.0 12.0 sition B₂O₃ 3.0 4.0 5.0 5.0 5.0 5.0 4.0 4.0 3.0 3.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 7.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 CaO 6.0 6.0 6.0 6.0 6.0 7.0 7.0 6.0 7.0 7.0 SrO 2.5 2.0 2.0 4.0 0.0 2.0 1.0 2.0 4.0 0.0 BaO 2.5 2.0 2.0 0.0 4.0 2.0 2.0 2.0 0.0 4.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.003 0.003 0.003 0.004 0.003 0.003 0.004 0.004 0.003 0.003 TiO₂ 0.011 0.011 0.011 0.011 0.001 0.002 0.001 0.002 0.001 0.002 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.07 4.71 4.64 4.64 4.64 4.99 5.15 5.15 5.66 5.66 Al₂O₃/B₂O₃ 4.33 3.50 2.80 2.80 2.80 2.60 3.25 3.25 4.00 4.00 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 6.67 5.00 4.00 4.00 4.00 3.80 4.75 4.75 6.00 6.00 RO 18.0 16.0 16.0 16.0 16.0 17.0 16.0 16.0 17.0 17.0 SrO + BaO 5.0 4.0 4.0 4.0 4.0 4.0 3.0 4.0 4.0 4.0 (MgO + CaO)/(SrO + BaO) 2.60 3.00 3.00 3.00 3.00 3.25 4.33 3.00 3.25 3.25 Al₂O₃/(10,000 × P₂O₅) 0.43 0.47 0.47 0.35 0.47 0.43 0.33 0.33 0.40 0.40 Al₂O₃/(1,000 × TiO₂) 1.18 1.27 1.27 1.27 14.00 6.50 13.00 6.50 12.00 6.00 CTE [×10⁻⁷/° C.] 40.1 37.6 37.5 37.4 38.0 39.3 37.4 37.8 38.8 39.5 Density [g/cm³] 2.61 2.57 2.57 2.54 2.59 2.57 2.55 2.56 2.55 2.60 Young's modulus [GPa] 83 82 82 82 81 81 82 82 83 81 Ps [° C.] 717 721 711 713 713 704 715 715 716 714 Ta [° C.] 772 777 767 768 768 758 771 771 772 770 Ts [° C.] 993 999 989 988 991 978 997 998 997 999 10⁴ dPa · s [° C.] 1,293 1,301 1,282 1,278 1,284 1,273 1,299 1,306 1,308 1,314 10³ dPa · s [° C.] 1,446 1,457 1,431 1,426 1,433 1,424 1,452 1,462 1,468 1,475 10^(2.5) dPa · s [° C.] 1,545 1,551 1,527 1,522 1,529 1,523 1,555 1,564 1,572 1,578 TL [° C.] 1,222 1,195 1,188 1,178 1,171 1,160 1,223 1,213 1,245 1,186 Log₁₀ηTL 4.6 5.0 4.9 5.0 5.1 5.1 4.7 4.8 4.5 5.1

TABLE 9 No. No. No. No. No. No. No. No. No. No. 81 82 83 84 85 86 87 88 89 90 Glass SiO₂ 64.9 64.9 65.9 66.9 65.9 66.9 66.9 67.9 66.9 65.9 compo- Al₂O₃ 14.0 14.0 14.0 14.0 14.0 14.0 14.0 14.0 13.0 14.0 sition B₂O₃ 4.0 4.0 4.0 4.0 4.0 4.0 3.0 3.0 4.0 4.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 7.0 7.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 CaO 6.0 6.0 7.0 7.0 6.0 6.0 7.0 7.0 5.0 5.0 SrO 4.0 0.0 1.0 0.0 1.5 0.5 1.0 0.0 2.5 2.5 BaO 0.0 4.0 2.0 2.0 2.5 2.5 2.0 2.0 2.5 2.5 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.011 0.005 0.004 0.003 0.01 0.008 0.008 0.008 0.006 0.006 TiO₂ 0.001 0.002 0.002 0.002 0.002 0.002 0.001 0.002 0.002 0.002 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 4.64 4.64 4.71 4.78 4.71 4.78 4.78 4.85 5.15 4.71 Al₂O₃/B₂O₃ 3.50 3.50 3.50 3.50 3.50 3.50 4.67 4.67 3.25 3.50 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 5.25 5.25 5.00 5.00 5.00 5.00 6.67 6.67 4.75 5.00 RO 17.0 17.0 16.0 15.0 16.0 15.0 16.0 15.0 16.0 16.0 SrO + BaO 4.0 4.0 3.0 2.0 4.0 3.0 3.0 2.0 5.0 5.0 (MgO + CaO)/(SrO + BaO) 3.25 3.25 4.33 6.50 3.00 4.00 4.33 6.50 2.20 2.20 Al₂O₃/(10,000 × P₂O₅) 0.13 0.28 0.35 0.47 0.14 0.18 0.18 0.18 0.22 0.23 Al₂O₃/(1,000 × TiO₂) 14.00 7.00 7.00 7.00 7.00 7.00 14.00 7.00 6.50 7.00 CTE [×10⁻⁷/° C.] 38.0 38.6 37.2 35.3 37.7 36.0 37.2 35.4 38.2 37.9 Density [g/cm³] 2.61 2.61 2.56 2.53 2.58 2.55 2.56 2.54 2.56 2.58 Young's modulus [GPa] 84 83 83 83 83 83 84 84 81 82 Ps [° C.] 718 716 719 723 719 723 730 733 714 720 Ta [° C.] 772 771 776 780 775 779 786 790 771 776 Ts [° C.] 989 992 998 1,004 999 1,005 1,009 1,015 998 1,000 10⁴ dPa · s [° C.] 1,276 1,286 1,291 1,305 1,295 1,304 1,310 1,322 1,306 1,299 10³ dPa · s [° C.] 1,422 1,434 1,442 1,464 1,444 1,456 1,462 1,482 1,466 1,450 10^(2.5) dPa · s [° C.] 1,519 1,531 1,538 1,571 1,542 1,553 1,561 1,592 1,572 1,549 TL [° C.] 1,178 1,207 1,192 1,270 1,189 1,266 1,221 1,285 1,211 1,195 Log₁₀ηTL 4.9 4.7 4.9 4.3 5.0 4.3 4.8 4.3 4.8 5.0

TABLE 10 No. No. No. No. No. No. No. No. No. No. 91 92 93 94 95 96 97 98 99 100 Glass SiO₂ 66.9 66.4 66.9 66.9 67.4 67.6 66.7 65.8 68.7 67.5 compo- Al₂O₃ 14.0 14.5 14.0 14.0 13.5 13.1 14.0 13.0 12.5 12.2 sition B₂O₃ 3.0 3.0 3.0 3.0 3.0 2.9 3.0 3.9 2.9 2.8 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 6.0 6.0 6.0 6.0 6.0 6.2 5.1 6.1 7.1 7.1 CaO 6.0 6.0 6.0 6.0 6.0 6.1 6.1 6.1 5.2 5.8 SrO 2.0 2.0 3.0 1.0 2.0 2.0 2.0 1.5 1.3 1.3 BaO 2.0 2.0 1.0 3.0 2.0 2.0 3.0 3.5 2.1 3.2 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.007 0.011 0.002 0.003 0.011 0.011 0.002 0.005 0.003 0.002 TiO₂ 0.002 0.013 0.012 0.011 0.011 0.01 0.008 0.013 0.012 0.011 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 4.78 4.58 4.78 4.78 4.99 5.17 4.75 5.07 5.48 5.51 Al₂O₃/B₂O₃ 4.67 4.83 4.67 4.67 4.50 4.48 4.73 3.29 4.37 4.36 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 6.67 6.83 6.67 6.67 6.50 6.60 6.46 4.85 6.85 6.86 RO 16.0 16.0 16.0 16.0 16.0 16.3 16.2 17.2 15.8 17.3 SrO + BaO 4.0 4.0 4.0 4.0 4.0 4.1 5.0 5.0 3.5 4.5 (MgO + CaO)/(SrO + BaO) 3.00 3.00 3.00 3.00 3.00 3.03 2.23 2.44 3.56 2.84 Al₂O₃/(10,000 × P₂O₅) 0.20 0.13 0.70 0.47 0.12 0.12 0.70 0.26 0.42 0.61 Al₂O₃/(1,000 × TiO₂) 7.00 1.12 1.17 1.27 1.23 1.31 1.75 1.00 1.05 1.11 CTE [×10⁻⁷/° C.] 37.2 37.0 37.1 37.4 37.4 37.4 38.4 39.7 39.2 39.7 Density [g/cm³] 2.58 2.58 2.56 2.59 2.57 2.57 2.61 2.61 2.58 2.61 Young's modulus [GPa] 84 84 84 83 83 83 83 81 83 82 Ps [° C.] 731 733 733 733 728 727 730 714 727 718 Ta [° C.] 787 789 789 789 785 784 787 727 784 775 Ts [° C.] 1,011 1,011 1,011 1,013 1,010 1,012 1,014 993 1,014 1,002 10⁴ dPa · s [° C.] 1,312 1,308 1,311 1,317 1,315 1,319 1,318 1,296 1,326 1,310 10³ dPa · s [° C.] 1,466 1,458 1,463 1,471 1,469 1,474 1,472 1,449 1,483 1,465 10^(2.5) dPa · s [° C.] 1,564 1,556 1,562 1,570 1,568 1,574 1,571 1,548 1,585 1,566 TL [° C.] 1,202 1,239 1,214 1,208 1,197 1,188 1,204 1,155 1,220 1,158 Log₁₀ηTL 5.0 4.6 4.9 5.0 5.1 5.2 5.0 5.4 4.9 5.4

TABLE 11 No. No. No. No. No. No. No. No. No. No. 101 102 103 104 105 106 107 108 109 110 Glass SiO₂ 67.2 67.2 68.4 68.1 67.9 67.9 67.9 66.9 67.4 67.1 compo- Al₂O₃ 12.3 12.2 12.5 12.7 13.0 12.5 13.0 13.0 13.1 13.5 sition B₂O₃ 3.4 2.6 2.9 5.1 2.8 2.8 2.8 3.8 3.7 2.8 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 7.2 8.1 8.1 5.4 5.1 6.1 5.6 6.1 6.1 5.6 CaO 6.4 7.3 4.5 5.2 6.6 6.6 6.6 6.6 6.5 6.6 SrO 1.3 1.3 2.3 0.0 1.5 2.0 0.5 1.5 1.5 1.5 BaO 2.1 1.2 1.2 3.4 3.0 2.0 3.5 2.0 1.5 2.8 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.005 0.003 0.002 0.011 0.002 0.005 0.003 0.004 0.003 0.003 TiO₂ 0.012 0.012 0.011 0.01 0.008 0.013 0.012 0.009 0.01 0.009 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.49 5.49 5.49 5.36 5.21 5.42 5.22 5.14 5.17 4.97 Al₂O₃/B₂O₃ 3.57 4.66 4.25 2.51 4.59 4.50 4.59 3.38 3.50 4.76 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 5.66 7.73 7.01 3.57 6.40 6.70 6.58 4.97 5.14 6.74 RO 17.0 17.9 16.1 14.0 16.2 16.7 16.2 16.2 15.7 16.5 SrO + BaO 3.4 2.5 3.5 3.4 4.5 4.0 4.0 3.5 3.0 4.3 (MgO + CaO)/(SrO + BaO) 4.00 6.07 3.66 3.06 2.59 3.17 3.06 3.61 4.19 2.82 Al₂O₃/(10,000 × P₂O₅) 0.25 0.41 0.62 0.12 0.65 0.25 0.43 0.33 0.44 0.45 Al₂O₃/(1,000 × TiO₂) 1.02 1.02 1.13 1.27 1.63 0.96 1.08 1.45 1.31 1.50 CTE [×10⁻⁷/° C.] 37.9 38.1 38.3 38.5 38.3 38.0 37.5 36.6 38.4 40.4 Density [g/cm³] 2.56 2.55 2.56 2.59 2.57 2.59 2.56 2.53 2.59 2.62 Young's modulus [GPa] 82 84 84 79 82 82 82 82 82 83 Ps [° C.] 713 721 726 714 726 722 727 717 719 728 Ta [° C.] 768 775 782 772 783 778 784 774 776 784 Ts [° C.] 994 996 1,010 1,007 1,013 1,006 1,013 999 1,003 1,010 10⁴ dPa · s [° C.] 1,298 1,293 1,318 1,325 1,323 1,314 1,322 1,303 1,306 1,315 10³ dPa · s [° C.] 1,456 1,446 1,474 1,485 1,481 1,472 1,481 1,457 1,461 1,470 10^(2.5) dPa · s [° C.] 1,558 1,545 1,574 1,586 1,582 1,572 1,584 1,556 1,560 1,571 TL [° C.] 1,183 1,208 1,247 1,197 1,202 1,188 1,181 1,173 1,180 1,200 Log₁₀ηTL 5.1 4.8 4.6 5.1 5.1 5.2 5.3 5.2 5.2 5.1

TABLE 12 No. No. No. No. No. No. No. No. No. No. 111 112 113 114 115 116 117 118 119 120 Glass SiO₂ 66.8 67.4 68.2 67.9 67.9 67.9 67.2 67.4 67.4 67.4 compo- Al₂O₃ 13.0 12.3 12.5 12.7 12.8 13.0 12.2 12.0 12.0 12.0 sition B₂O₃ 3.0 2.8 3.0 3.0 3.0 3.0 2.8 2.0 2.0 2.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 5.1 7.0 6.0 6.0 5.8 5.7 7.1 6.5 6.5 6.5 CaO 6.6 6.2 6.5 6.3 6.5 6.3 7.3 7.0 7.0 6.0 SrO 2.5 1.2 1.7 1.7 1.4 1.4 1.3 3.0 2.0 4.0 BaO 3.0 3.0 2.0 2.3 2.6 2.6 2.2 2.0 3.0 2.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.004 0.004 0.003 0.003 0.003 0.003 0.004 0.003 0.003 0.003 TiO₂ 0.009 0.011 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.009 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.14 5.48 5.46 5.35 5.33 5.22 5.52 5.62 5.62 5.62 Al₂O₃/B₂O₃ 4.39 4.39 4.17 4.23 4.25 4.33 4.40 6.00 6.00 6.00 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 6.12 6.89 6.17 6.23 6.17 6.23 6.95 9.25 9.25 9.25 RO 17.2 17.4 16.2 16.3 16.3 16.0 17.8 18.5 18.5 18.5 SrO + BaO 5.5 4.2 3.7 4.0 4.0 4.0 3.5 5.0 5.0 6.0 (MgO + CaO)/(SrO + BaO) 2.12 3.14 3.38 3.08 3.06 3.00 4.12 2.70 2.70 2.08 Al₂O₃/(10,000 × P₂O₅) 0.32 0.31 0.42 0.42 0.43 0.43 0.30 0.40 0.40 0.40 Al₂O₃/(1,000 × TiO₂) 1.44 1.12 1.25 1.27 1.28 1.30 1.22 1.20 1.20 1.33 CTE [×10⁻⁷/° C.] 39.1 38.9 37.7 38.1 37.8 37.3 39.1 40.9 41.6 41.2 Density [g/cm³] 2.57 2.59 2.56 2.57 2.57 2.57 2.57 2.61 2.62 2.63 Young's modulus [GPa] 82 83 82 82 82 82 83 84 83 83 Ps [° C.] 721 719 726 723 725 728 717 722 721 721 Ta [° C.] 778 775 783 780 783 786 773 777 776 777 Ts [° C.] 1,004 1,001 1,010 1,008 1,011 1,016 996 999 1,000 1,000 10⁴ dPa · s [° C.] 1,310 1,309 1,318 1,316 1,320 1,326 1,300 1,302 1,305 1,304 10³ dPa · s [° C.] 1,466 1,465 1,476 1,473 1,477 1,482 1,455 1,456 1,461 1,460 10^(2.5) dPa · s [° C.] 1,566 1,566 1,576 1,575 1,578 1,583 1,556 1,557 1,562 1,560 TL [° C.] 1,227 1,183 1,201 1,196 1,191 1,207 1,192 1,218 1,204 1,236 Log₁₀ηTL 4.7 5.2 5.1 5.1 5.2 5.1 5.0 4.7 4.9 4.6

TABLE 13 No. No. No. No. No. No. No. No. No. No. 121 122 123 124 125 126 127 128 129 130 Glass SiO₂ 67.4 68.4 68.4 68.4 68.4 67.2 67.5 67.2 67.2 67.2 compo- Al₂O₃ 12.0 12.0 12.0 12.0 12.0 13.0 13.0 13.3 13.0 13.0 sition B₂O₃ 2.0 2.0 2.0 2.0 2.0 4.0 3.7 3.7 3.7 3.7 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 6.5 6.5 6.5 6.5 6.5 6.0 6.0 6.0 6.3 6.0 CaO 8.0 8.0 7.0 7.0 6.0 6.5 6.5 6.5 6.5 6.5 SrO 2.0 1.0 2.0 1.0 3.0 1.5 1.5 1.5 1.5 1.5 BaO 2.0 2.0 2.0 3.0 2.0 1.7 1.7 1.7 1.7 2.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.003 0.004 0.003 0.003 0.003 0.001 0.001 0.001 0.001 0.001 TiO₂ 0.01 0.01 0.009 0.01 0.01 0.008 0.007 0.009 0.008 0.008 Cl 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.62 5.70 5.70 5.70 5.70 5.17 5.19 5.05 5.17 5.17 Al₂O₃/B₂O₃ 6.00 6.00 6.00 6.00 6.00 3.25 3.51 3.59 3.51 3.51 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 9.25 9.25 9.25 9.25 9.25 4.75 5.14 5.22 5.22 5.14 RO 18.5 17.5 17.5 17.5 17.5 15.7 15.7 15.7 16.0 16.0 SrO + BaO 4.0 3.0 4.0 4.0 5.0 3.2 3.2 3.2 3.2 3.5 (MgO + CaO)/(SrO + BaO) 3.63 4.83 3.38 3.38 2.50 3.91 3.91 3.91 4.00 3.57 Al₂O₃/(10,000 × P₂O₅) 0.40 0.30 0.40 0.40 0.40 1.30 1.30 1.33 1.30 1.30 Al₂O₃/(1,000 × TiO₂) 1.20 1.20 1.33 1.20 1.20 1.63 1.86 1.48 1.63 1.63 CTE [×10⁻⁷/° C.] 40.4 39.0 39.1 39.4 39.8 37.1 37.1 37.2 37.4 37.8 Density [g/cm³] 2.60 2.57 2.58 2.60 2.60 2.54 2.54 2.55 2.55 2.56 Young's modulus [GPa] 84 84 84 83 83 82 83 82 83 82 Ps [° C.] 722 725 725 725 726 720 723 724 722 721 Ta [° C.] 778 782 782 782 783 776 780 781 778 777 Ts [° C.] 999 1,008 1,009 1,009 1,010 1,002 1,006 1,006 1,003 1,003 10⁴ dPa · s [° C.] 1,300 1,315 1,323 1,322 1,319 1,309 1,314 1,309 1,307 1,308 10³ dPa · s [° C.] 1,455 1,473 1,480 1,480 1,477 1,462 1,468 1,463 1,460 1,462 10^(2.5) dPa · s [° C.] 1,554 1,574 1,584 1,582 1,579 1,560 1,566 1,561 1,558 1,561 TL [° C.] 1,216 1,219 1,201 1,210 1,222 1,182 1,169 1,197 1,182 1,172 Log₁₀ηTL 4.7 4.8 5.1 5.0 4.9 5.2 5.4 5.0 5.2 5.3

TABLE 14 No. No. No. No. No. No. 131 132 133 134 135 136 Glass SiO₂ 67.6 68.1 67.9 68.3 67.4 67.6 compo- Al₂O₃ 12.3 12.3 12.3 12.3 13.0 13.1 sition B₂O₃ 2.8 2.8 2.8 2.8 3.7 3.4 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 7.0 6.5 6.8 6.5 6.1 6.1 CaO 6.2 6.2 6.2 6.2 6.5 6.5 SrO 1.4 1.4 1.5 1.5 1.5 1.5 BaO 2.6 2.6 2.4 2.3 1.5 1.7 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.001 0.001 0.001 0.001 0.001 0.001 TiO₂ 0.008 0.009 0.008 0.008 0.008 0.008 Cl 0.001 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.50 5.54 5.52 5.55 5.17 5.16 Al₂O₃/B₂O₃ 4.39 4.39 4.39 4.39 3.50 3.85 Li₂O + Na₂O + K₂O 0.0 0.0 0.0 0.0 0.0 1.0 (Al₂O₃ + MgO)/B₂O₃ 6.89 6.71 6.82 6.71 5.15 5.65 RO 17.2 16.7 16.9 16.5 15.7 15.8 SrO + BaO 4.0 4.0 3.9 3.8 3.0 3.2 (MgO + CaO)/(SrO + BaO) 3.30 3.18 3.33 3.34 4.20 3.94 Al₂O₃/(10,000 × P₂O₅) 1.23 1.23 1.23 1.23 1.30 1.31 Al₂O₃/(1,000 × TiO₂) 1.54 1.37 1.54 1.54 1.63 1.64 CTE [×10⁻⁷/° C.] 38.9 38.9 38.8 38.2 36.8 36.9 Density [g/cm³] 2.58 2.58 2.58 2.57 2.53 2.55 Young's modulus [GPa] 83 83 83 83 83 83 Ps [° C.] 720 721 722 723 720 724 Ta [° C.] 777 778 779 780 777 781 Ts [° C.] 1,002 1,006 1,005 1,009 1,004 1,007 10⁴ dPa · s [° C.] 1,311 1,318 1,315 1,321 1,311 1,313 10³ dPa · s [° C.] 1,465 1,474 1,470 1,476 1,466 1,466 10^(2.5) dPa · s [° C.] 1,564 1,573 1,570 1,576 1,564 1,563 TL [° C.] 1,170 1,179 1,178 1,186 1,174 1,192 Log₁₀ηTL 5.3 5.3 5.3 5.2 5.3 5.1 No. No. No. No. No. 137 138 139 140 141 Glass SiO₂ 67.5 70.9 57.9 57.7 67.9 compo- Al₂O₃ 13.2 12.0 13.0 14.0 19.0 sition B₂O₃ 3.3 5.0 9.0 5.0 2.0 (mol %) Li₂O 0.0 0.0 0.0 0.0 0.0 Na₂O 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 MgO 6.1 4.0 8.0 8.0 4.0 CaO 6.5 4.0 5.0 3.0 4.0 SrO 1.6 2.0 1.8 2.3 2.0 BaO 1.7 2.0 5.3 10.0 2.0 SnO₂ 0.1 0.1 0.1 0.1 0.1 P₂O₅ 0.001 0.011 0.005 0.002 0.008 TiO₂ 0.008 0.01 0.008 0.013 0.012 Cl 0.001 0.001 0.001 0.001 0.001 SiO₂/Al₂O₃ 5.11 5.91 4.45 4.12 3.57 Al₂O₃/B₂O₃ 4.00 2.40 1.44 2.80 9.50 Li₂O + Na₂O + K₂O 2.0 0.0 0.0 0.0 0.0 (Al₂O₃ + MgO)/B₂O₃ 5.85 3.20 2.30 4.40 11.00 RO 15.9 12.0 20.0 23.3 12.0 SrO + BaO 3.3 4.0 7.1 12.3 4.0 (MgO + CaO)/(SrO + BaO) 3.82 2.00 1.83 0.89 2.00 Al₂O₃/(10,000 × P₂O₅) 1.32 0.11 0.26 0.70 0.24 Al₂O₃/(1,000 × TiO₂) 1.65 1.20 1.63 1.08 1.58 CTE [×10⁻⁷/° C.] 36.3 33.1 44.7 50.7 32.1 Density [g/cm³] 2.55 2.50 2.68 2.90 2.58 Young's modulus [GPa] 83 78 79 81 86 Ps [° C.] 725 715 654 679 759 Ta [° C.] 782 776 703 731 818 Ts [° C.] 1,007 1025 905 929 1,043 10⁴ dPa · s [° C.] 1,314 1,361 1,169 1,197 1,350 10³ dPa · s [° C.] 1,469 1,538 1,304 1,332 1,488 10^(2.5) dPa · s [° C.] 1,567 1,653 1,387 1,413 1,582 TL [° C.] 1,184 1,207 1,100 1,131 >1,450 Log₁₀ηTL 5.2 5.3 5.3 6.4 Unmea- surable

First, a glass batch prepared by blending glass raw materials so as to achieve the glass composition shown in each Table was loaded in a platinum crucible, and then melted at from 1, 600° C. to 1,650° C. for 24 hours. In melting the glass batch, molten glass was stirred to be homogenized by using a platinum stirrer. Next, the molten glass was poured on a carbon sheet and formed into a sheet shape, followed by being annealed at a temperature around an annealing point for 30 minutes. Each of the resultant samples was evaluated for its average thermal expansion coefficient CTE within a temperature range of from 30° C. to 380° C., density, Young's modulus, strain point Ps, annealing point Ta, softening point Ts, temperature at a viscosity at high temperature of 10⁴ dPa·s, temperature at a viscosity at high temperature of 10³ dPa·s, temperature at a viscosity at high temperature of 10^(2.5) dPa·s, liquidus temperature TL, and viscosity log₁₀ ηTL at the liquidus temperature TL.

The average thermal expansion coefficient CTE within a temperature range of from 30° C. to 380° C. is a value measured with a dilatometer.

The density is a value measured by a well-known Archimedes method.

The Young's modulus refers to a value measured by a well-known resonance method.

The strain point Ps, the annealing point Ta, and the softening point Ts are values measured in accordance with methods specified in ASTM C336 and C338.

The temperatures at viscosities at high temperature of 10⁴ dPa·s, 10³ dPa·s, and 10²⁻⁵ dPa·s are values measured by a platinum sphere pull up method.

The liquidus temperature TL is a temperature at which a crystal precipitates after glass powder that has passed through a standard 30-mesh sieve (500 μm) and remains on a 50-mesh sieve (300 μm) is placed in a platinum boat and kept for 24 hours in a gradient heating furnace.

The liquidus viscosity log₁₀ ηTL is a value obtained by measuring the viscosity of the glass at the liquidus temperature TL by a platinum sphere pull up method.

As apparent from Tables 1 to 14, each of Sample Nos. 1 to 137, in which the glass composition is restricted to the predetermined range, has a Young's modulus of 80.1 GPa or more, a strain point of 681° C. or more, a liquidus temperature of 1,285° C. or less, and a liquidus viscosity of 10^(4.29) dPa·s or more, and is hence considered to have satisfactory productivity, be able to reduce thermal shrinkage in a LTPS process, and allow for less occurrence of defects due to deflection even when the glass sheet is increased in size and reduced in thickness. Accordingly, Sample Nos. 1 to 137 are each suitable as a substrate for an OLED device.

Meanwhile, Sample No. 138 had a temperature at a viscosity at high temperature of 10^(2.5) dPa·s as high as 1,653° C. and a Young's modulus as low as 77.5 GPa. Sample No. 139 had a strain point as low as 654° C. Sample No. 140 had an average thermal expansion coefficient within a temperature range of from 30° C. to 380° C. as high as 50.7×10⁻⁷/° C. and a strain point as low as 679° C. Sample No. 141 had a liquidus temperature of more than 1,450° C., and its liquidus viscosity could not be measured.

INDUSTRIAL APPLICABILITY

The alkali-free glass sheet of the present invention is suitable as a substrate for an OLED device, particularly for an OLED TV. Other than those applications, the alkali-free glass sheet of the present invention is also suitable, for example, as a substrate for a flat panel display, such as a liquid crystal display, a cover glass for an image sensor, such as a charge coupled device (CCD) or a contact image sensor (CIS), a substrate and a cover glass for a solar cell, or a substrate for an OLED lighting device. 

1. An alkali-free glass sheet, which has a content of Li₂O+Na₂O+K₂O of from 0 mol % to 0.5 mol % in a glass composition, and has a Young's modulus of 78 GPa or more, a strain point of 680° C. or more, and a liquidus temperature of 1,450° C. or less.
 2. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet comprises as the glass composition, in terms of mol %, 58% to 68% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 4% to 10% of MgO, 2% to 10% of CaO, and 2% to 13% of SrO+BaO.
 3. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet comprises as the glass composition, in terms of mol %, 58% to 67% of SiO₂, 11% to 18% of Al₂O₃, 1.5% to 6% of B₂O₃, 0% to 0.5% of Li₂O+Na₂O+K₂O, 4% to 10% of MgO, 2% to 10% of CaO, 1.5% to 8% of SrO, and 1.5% to 8% of BaO, and is substantially free of As₂O₃ and Sb₂O₃.
 4. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet further comprises 0.001 mol % to 1 mol % of SnO₂.
 5. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet has a strain point of 690° C. or more.
 6. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet has a Young's modulus of more than 80 GPa.
 7. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet has an average thermal expansion coefficient within a temperature range of from 30° C. to 380° C. of from 30×10⁻⁷/° C. to 50×10⁻⁷/° C.
 8. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet has a liquidus viscosity of 10^(4.5) dPa·s or more.
 9. The alkali-free glass sheet according to claim 1, wherein the alkali-free glass sheet is used for an OLED device. 